Grassland Degradation as Influenced by Climate Change in Balagaer River
Watershed of Inner Mongolia, China
Abstract
China is home to 12% of the world’s grasslands; second largest in the
world. The productivity of Chinese grasslands rapidly declined from 10%
degraded in 1970 to 90% degraded by the 2000s. Inner Mongolia, China,
is composed of 67%, mainly temperate, grasslands. From 1947-2009 human
and livestock populations in Inner Mongolia increased from 5.6-24.7
million and 8.4-96.0 million, respectively. These changes were not only
due to rising population increasing food demand, but also policy and
lifestyle changes. Though climate change and overgrazing are dominant
drivers of degradation, research shows that policies increasing
privatization of land rights have significant impacts, namely the
Household Production Responsibility System (HPRS) of 1949. In China,
grassland degradation is linked to environmental problems of sandstorms,
losses of biodiversity and carbon sinks, and droughts. Grassland
degradation led to widespread public health concerns including dust
storms originating from the arid rangelands of Inner Mongolia that swept
pollution across major population centers in China and other Asian
countries. Inner Mongolia climate change is evident: from 1951-2009 mean
temperature increased at 0.28°C per decade, doubling the global linear
warming trend of 0.138°C. This temperature increase was accompanied by a
9.9 mm decrease in precipitation per decade, resulting in decreased
gross primary productivity measured by Normalized Difference Vegetation
Index (NDVI). This study aims to quantify the Balagaer River Watershed
degradation in Inner Mongolia, China from 2000-2019 and explore
correlations between climate change, NDVI values, and degradation
status. Researchers used GIS analysis of MODIS NDVI data and regressions
of NDVI on precipitation and potential evapotranspiration (PET).
Differences in NDVI were calculated between years and classified
degradation into three categories: slightly, moderately, and heavily
degraded. These calculations quantified the percentage of the watershed
occupied by each category. Correlations between NDVI and precipitation
and NDVI and PET were conducted using Excel at three temporal scales:
annual, pre-growing season (October to April), and growing season (May
to September). It is expected that decreased precipitation contributed
to decreased NDVI.